


Veritas Diaboli

by Enochian Things (Salr323)



Category: Supernatural
Genre: Angst, Coda, Episode: s11e10 The Devil in the Details, M/M, POV Dean Winchester
Language: English
Status: Completed
Published: 2016-01-25
Updated: 2016-01-25
Packaged: 2018-05-16 06:42:40
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,129
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5818084
Author URL: https://archiveofourown.org/users/Salr323/pseuds/Enochian%20Things
Summary: <blockquote class="userstuff">
              <p>This thing, tentative and unacknowledged between them for so long, is precious nonetheless and his heart twists at the allusion falling obscene from Lucifer's lips.  He looks away, sickened.  Lucifer's probably lying.  He can't think about what it means if he isn't; it would be too cruel, after all this time, to hear the truth of it from anyone other than Cas.</p><p>(Coda 11.10)</p>
            </blockquote>





	Veritas Diaboli

**Author's Note:**

> Title means 'The truth of the devil'

In the brash light of the bunker, Sam raises the gun and aims it right at Cas’s head, arms locked and finger tight on the trigger.

Dean's heart stutters to a halt. “Sam!” he barks. “The hell?”

Sam’s jaw is tense, his whole face bleak as fucking stone. “It’s not him,” he says in a voice like granite. “Dean, it’s not Cas.”

“What?” He half-lifts his own gun, reluctant to point it at Cas. “The fuck are you talking about?”

At that Cas turns to face him, head tilted to the side. “Dean?” he says, just like he always does, half query and half plea, his usual disheveled weariness. 

For a long moment they share a look. And Dean wants – _needs –_ Sam to be wrong. This is _Cas_ , his friend, his— Whatever.

But Sam's not wrong; there’s something off behind Cas’s eyes, there’s something missing. Dean raises his weapon higher, firms his grip. “What’s going on, Cas?” His mouth and throat are so dry the words come out a rasp. “Talk to me, man.”

For a beat longer, Cas holds his gaze. And then he laughs, a weird effete laugh, and shakes his head. He’s moving wrong now, his whole body louche in a way that Cas isn’t. “Oh,” he says through the laughter, “as much fun as this has been, I can’t kid you guys any longer. You know me too well.” He spreads his arms, his hands, as if to say ' _ta-da!'_ “You got me, Sam. I’m back.”

Sam looks ill, physically sick, but Dean’s a resolute couple of steps behind him; he doesn't want to understand. “Sam?”

“It’s Lucifer,” he says, grinding the words between his teeth. “Dean, it’s Lucifer.”

It feels like the world has risen up to slam him in the face; his breath is gone, his chest squeezed shut in disbelief. “What?” he manages to get out through his strangled throat. “That’s not— That’s impossible. Cas wouldn’t—” His eyes lock onto Sam’s, desperate for confirmation. “Cas would _never_ say yes.”

Sam just gives a desperate half shrug, his weapon still aimed at the thing that was Cas. “He must have.”

“Oh, he did,” Lucifer smirks, the words obscene coming from those lips. “He wanted it Dean. He _asked_ for it.”

“Shut up,” he snarls, edging a step closer, finger flexing on the trigger. “Just shut your mouth.”

“Or what?” Lucifer says. “You’ll shoot me?” He makes a casual gesture with his fingers and the gun is suddenly white hot and Dean drops it with a harsh cry, the stench of his own scorched flesh rank in his nose. “You see,” Lucifer says, taking a step closer, “things are gonna be a little different around here now.” He glances about the bunker. “Nice secret hideout, by the way. I like what you’ve done with the place.” He smiles and Dean has to look away, can’t bear to see that corrupt expression carved into the gentle lines and angles of Cas’s face. It turns his stomach. “And what you’ve done with it,” Lucifer continues, “is hand it over to me.”

Dean ignores all his bullshit; there’s only one thing he cares about now. “Where’s Cas?”

“Castiel?” Lucifer feigns surprise. “Oh, he had to go.” He leans a little closer. “Honestly, Dean, if you'd smelled the self-loathing in here…” He shakes his head, waves a hand in front of his nose. “Phew, I’m telling you, Castiel reeked of it.” He smiles and his eyes are bright and cold as a winter sky. “I suppose I should thank _you_ for that. Without you, Castiel might never have relinquished his vessel and then where would we be?”

A fist clamps around his heart, iron-cold and tightening. “The fuck are you talking about?”

“Don’t listen to him.” Sam still has his weapon, he's circling around Lucifer toward Dean with the gun leveled. “He’s the Father of Lies, remember?”

“Me?” Lucifer says, hand to heart. “Sam, you know I've never lied to you.”

“He’s just screwing with you, Dean.”

Lucifer laughs and it's cold, so cold as he turns back to Dean. “Well,” he says, “he's right. I _am_ screwing with you. But I'm not lying. Honestly, Dean – and I’m not saying this to be polite; I really do mean it – I couldn’t have done a better job on Castiel myself. Well done you.” He steps back, arms spread wide. “You see? All those years in Hell didn’t go to waste after all; you don’t even need a knife to gut a man anymore. You're a genius at destroying the people who love you, Dean. You're an _artist_.”

It sets Dean reeling, rocks him back a step. He knows that this is fucking _Lucifer_ talking, but the horror burning in the pit of his stomach doesn't stem from the devil's words; it stems from the truth he hears in them. Dean's always known he's poison. 

“Leave him alone!” Sam snarls.

“Oh Sam, it’s too late to play the hero now.” Lucifer shakes his head, playacting sorrow; there are lies in every gesture, even when there's truth in his words. “I gave you your chance and you blew it, remember? I’m sorry, but you and me – us – we’re over, Sam. I just don’t need you anymore.” And with another flick of his hand Sam is slamming into the wall on the far side of the library, collapsing into a heap among the scattered books. There's blood on his face, trickling from a wide gash in his forehead.

Dean’s moving before he can think, stumbling to his knees next to his brother. “Sam—”

“Oh, he’s still alive,” Lucifer says, bored. “If I wanted him dead…” He lifts his fingers, as if to snap them. “But we’re a team now, Dean: you, me and Sam. And we have a job to do.” 

Dean scrambles to his feet, standing over Sam as Lucifer stalks toward them with precise, predatory strides that are so unlike Cas that it hurts to watch. “We're not a fucking team,” Dean snarls.

“Now, don't be like that,” Lucifer says, reaching out to clasp Dean's shoulder. “This could be a good thing.”

Dean stares at the hand on his shoulder, at the creeping wrongness of it, and then lifts his eyes to meet the devil's. They’re achingly familiar, yet alien, and he looks past them into the evil coiling behind that cold blue gaze, and then past that too; he has to believe that Cas is still in there, that maybe he’s listening. He hopes to God he’s listening. “You should know this,” Dean says, “I'm gonna kill you. I’m gonna save Cas, and then I’m gonna take you apart. You understand that?”

Lucifer gives a dramatic sigh. “Am I supposed to be _afraid_?”

“I don’t give a shit what you are, I’m just telling you how it’s gonna go down.”

“Hmm,” Lucifer says, turning on his heel and pacing in a small circle, coming back to stand in front of Dean. “Just look at all that bravado. Castiel loved that about you, by the way. Did you know? He couldn't get enough of all that pointless machismo.” He rolls his eyes. “It’s pathetic, isn't it? Once, Castiel could have peeled off your skin with a thought, dissipated your atoms to the far reaches of the universe; I can’t even imagine why he found your apish posturing so … arousing. But then my brother always was the black sheep of the family. They used to say he was made wrong, broken from the get-go.”

It's bitter, listening to this crap in Cas's gravelly voice, seeing his face twisted into mockery. And it burns, ignites something vicious and primal. Dean clenches his fingers, nails biting into his palms to keep from throwing a futile punch. “Cas,” he says, working the words past the raw anger in his throat, “is the best of you all. He’s worth ten thousand of you, of all of you put together. He’s—” He swallows. “You think you know him? You don’t know shit.”

Lucifer cocks an eyebrow. “I know why he said ‘yes’.”

Dean locks his jaw, no answer to that, because _why the fuck?_ But he's not going to ask.

“Oh go on,” Lucifer says, like it's a game. “I know you want to.” 

“Nothing that comes out of your mouth is the truth,” Dean says. “I don't care what you say.”

“I'll give you a clue...”

“Fuck you.”

“Is that an offer?” He leans in with a lecherous smirk. “Because I’m sure Castiel wouldn’t object.” He twitches an eyebrow. “Know what I mean?”

And this is a whole new kind of fear, of horror. This thing, tentative and unacknowledged between them for so long, is precious nonetheless and his heart twists at the allusion falling obscene from Cas's lips. He looks away, sickened. Lucifer's probably lying. He can't think about what it means if he isn't; it would be too cruel, after all this time, to hear the truth of it from anyone other than Cas.

“Did you know?” Lucifer says, reaching up to touch Dean's face. His fingers – Cas's fingers – are warm, gentle in the way Dean has only dared imagine late at night when he's had too much to drink. His heart flutters despite himself and he closes his eyes, wills himself not to respond. It's not Cas. _It's not Cas_. “Did you know how much he _yearned_ for this?” There's a contemptuous twist in Lucifer's voice. “Castiel was created for such great things, for eternity and the far reaches of the universe, and yet, at the end, this – _you_ – were what he put at the center of his wretched existence.” Suddenly his hand is harsh on Dean's face, grasping his chin in a crushing grip, forcing Dean to open his eyes. “I should ask you how you did it,” Lucifer says in a voice that’s neither Cas's growl nor Lucifer's folksy charm. It's dark and barbed and makes Dean think of sulfur and iron. “How did you corrupt an _angel_ , little monkey-man? How did you strip away his celestial intent, his purpose and his _power_ , and reduce him to this? To this abject creature filled with self-loathing and rage. How did you do it, Dean? How did you make him feel so worthless, so _expendable_ , that he'd give up his true vessel to _me_?”

“I didn't do anything,” Dean growls. The denial is difficult to form past Lucifer's vice-like fingers biting into his skin. But he can't be right; Dean can't be the reason Cas said yes to the fucking devil. “You're lying.” 

Lucifer's closer now, boring into him with those ice-chip eyes. “Oh,” he says as a delighted smile curls the cold line of his mouth, “well this is almost too good. This is... Don't tell me it was nothing more than neglect, Dean. That there was no purpose to it, no intention to destroy, just the accidental indifference of a man who simply didn’t care?”

Dean swallows, his heart kicking hard against his ribs. He's wrong; Dean did care. He cared too damn much. He knows Cas hasn't been himself recently, that he's had a hard time of it the past few weeks, months. Hell, years. But Dean's kept his distance, hasn't let himself get too close, for good fucking reason. It's not neglect; it's fear, because what he feels for Cas is so profound, so complicated and dangerous— 

And Lucifer can't know. He can never know, because if he knows then he's got Dean over a barrel and the lines he would cross to keep Cas safe scare him shitless. “Cas is a big boy,” he makes himself say. “He can take care of himself. And if he said yes to you then he had a fucking reason.”

“ _If_ he said yes? Rules are rules, Dean. You _know_ he said yes. And you know I'm telling the truth: Castiel only did this because he knew he was useless to you. Unwanted. _Expendable_.”

The truth of that batters about Dean's ears like wings, leathery and sulfurous, blotting out the world until all he can hear is his own guilty conscience: _you did this, you did this to Cas_. 

But he can't let Lucifer know how close he's gotten, he can't give him that power. Gritting his teeth, Dean forces a smile. “Or maybe he has a plan you can't even imagine, you dick.”

Lucifer scoffs. “Castiel? Well that's unlikely. He never was very imaginative.” 

Dean doesn't try to reply, it's all he can do to meet Lucifer's eye and not see Cas gazing back at him. He thinks of all the times he could have touched that face with tenderness, of how he might never get the chance again, and suddenly all the reasons that held him back feel shallow, mere ghosts of themselves. _  
_

_This is regret_ , he thinks. _This is what 'too fucking late' feels like_.

Behind him, Sam shifts as consciousness returns and Lucifer's cold gaze arrows down toward him. 

Dean puts himself between them. “So what's your plan?” he says, drawing Lucifer's attention back to him, giving Sam time to recover. “All the angels in heaven couldn't stop the Darkness. How are you going to kill it?”

“Not kill it,” Lucifer says. “Banish it. Send it back where it belongs, lock it away.”

“And then?” 

“Then?” Lucifer smiles, a true devil's smile, and shakes his head. “No spoilers, Dean, or you'll ruin the—”

And suddenly there's bright light, a vortex spiraling out from somewhere behind and beneath Dean's feet. A flash of rage blazes in Lucifer's eyes and after it – a moment, barely there – an expression of triumph. And Dean's heart soars, reaches out toward it, because it's Cas. He knows it, feels it in the depths of his soul. In the space between heartbeats he sees Cas, their eyes lock, and then he's gone. Lucifer is gone.

And Dean's alone in the bunker with Sam, who's sitting breathless on the floor, one hand in the center of the angel-banishing sigil he's scrawled onto the floor in his own blood. “If we don't invite him in, he can't get back inside, right?” Sam gasps.

“Right,” Dean says. But his head's spinning, his legs are weak, and he's sliding to the floor next to Sam because all he can think is _I saw Cas._

Silence reaches up to wrap around them both and for a long time they just sit there, the enormity of what's just happened sinking its bloody teeth into them. Eventually Sam shakes himself, breaks out of the torpor. “We'll get him back,” he says. “We'll get Cas back.”

“Yeah.” And Dean has to believe it's true; it's all he's got left to hold on to. He tries to clear his throat, swallows hard. “I saw him,” he says at last, eyes dry but voice rough with the tears he won't let fall. Not here, not in front of Sammy. “He's still in there, Sam. I saw him.”

Sam closes his eyes, compassion and horror flitting across his face. It makes Dean's skin crawl because Sam knows, only Sam knows, what it's like to have the devil inside your head. But then his brother takes a breath and looks at Dean, his mouth set and determined. “That's good,” he says with a nod. “We know he's still there. That's a good thing.” He lifts a bloody hand to his forehead, cautiously prods at the wound. 

Dean knows he should get him to the bathroom, sort that out, but all he can think about is Cas feeling so despairing that he'd throw himself to the devil. “Lucifer was right—” His voice falters, a harsh scratch. “This is on us, Sam. On me.” 

“Dean—”

“No, it's true.” He knows it's true and it scares the crap out of him that the truth has come from Lucifer: Father of Lies, King of the Douchebags. There are strings to this truth, traps and pitfalls, but it's the truth nonetheless and Dean can't ignore it. “Cas said yes because of me.”

“All that matters,” Sam says, “is getting him back.”

But that's not all that matters, not this time. “He's our friend, Sam. He's always been there for us, he's given everything for us, and we—” It hurts so much, this devil's truth, that he almost can't breathe around it. “We were so wrapped up in our own crap that we didn't see this coming.”

After a beat, Sam says, “How could we have seen _this_ coming?”

Dean just shakes his head, because it's clear now. Like glass shards, like a bitter night full of stars, it's all painfully clear. This has been coming for years: since Cas first rebelled, since he lost his home and his family, since he tried to fill the void left by his dick of a father and lost himself entirely. Since Purgatory. Since Metatron stole the last vestige of his self-respect along with his grace. Since Dean threw him out alone into a friendless world. Since Naomi screwed with his mind and made him a killer. Since Rowena turned him into a monster. Since he failed and failed and failed again. 

And not once was Dean there to pick up the pieces, all he ever did was demand more until Cas thought he had nothing left to give but his life. He swallows a lump of guilt and says, “We should have taken better care of him, Sam.” 

In silence Sam climbs to his feet and holds out a hand to Dean, to help him up. “We'll get him back,” he says, steady as a rock. “We will. We just gotta keep grinding.”

Dean looks at that hand, blood-smeared and strong, and after a moment reaches out to take it, hauls himself back to his feet. Back into the fight. “Right,” he says, because there's no other answer to give. They _will_ get him back. And when they do, he'll make it right. He'll tell Cas exactly what he means to him. He'll make him understand that he's the opposite of expendable, that to Dean he is _everything_ : his anchor, his rock, his north fucking star.

He fixes his eyes on Sam, sees the sympathy there and for once doesn't duck it; there's been too much hiding, too much left unsaid when it comes to Cas. Maybe Sam knows the truth already, maybe he doesn't, but either way it's time Dean stopped pretending.

“We're gonna save Cas,” he says, and it's a promise, a sacred fucking oath. “We're gonna save Cas. We're gonna ice the devil and we're gonna shank the Darkness. And anyone that gets in our way? Well... God help them.”

Sam smiles, his face bloody and eyes granite-hard. “Not even God could help them, Dean.”

And ain't that the fuckin' truth?

**Author's Note:**

> Thanks for reading my take on this, I hope you enjoyed it - can't wait to see where they go with it in the show! :)


End file.
